QUPLAS Marco G. Giammarchi Istituto Nazionale Fisica Nucleare – Milano On behalf of the QUPLAS group (Collaboration) Q U P L A S QUantum Interferometry, decoherence and gravitational studies with Positrons and LASers Outline of talk: Home of the Experiment: L-NESS Laboratory of the Politecnico di Milano - Polo territoriale di Como. QUPLAS Concept QUPLAS Physics QUPLAS Proposal and Financial Issues 10/10/2017 Quplas CSN2 - July 2015

The QUPLAS Collaboration Università degli Studi di Milano and Infn Milano S. Castelli, S. Cialdi, M. Giammarchi*, M. Longhi, G. Maero, S. Olivares, M. Paris, M. Potenza, M. Romè, S. Sala, S. Siccardi, D. Trezzi Politecnico di Milano (Polo territoriale di Como) S. Aghion, M. Bollani (IFN del CNR), G. Consolati, R. Ferragut, M. Leone Albert Einstein Center – Laboratory for HEP – University of Bern A. Ariga, T. Ariga, A. Ereditato, C. Pistillo, P. Scampoli Dep.t of Chemistry, University of Bath K. Edler R. Greaves (Los Angeles, formerly at First Point Scientific) 10/10/2017 Quplas CSN2 - July 2015

Ps : the truly elementary atom A pure QED system where spin-orbit and hyperfine effects are of the same order Our systems of interest : Electron (an elementary fermion) Positron (the antifermion) Positroniuim (Ps, a particle/antiparticle symmetric system) 10/10/2017 Quplas CSN2 - July 2015

Positrons and Positronium (Ps) e+ A conversion target ortho-Ps is short lived But its lifetime can be increased by exciting it on a Rydberg (high-n) state 10/10/2017 Quplas CSN2 - July 2015

Introduction to the concept of Quantum Interferometry of Ps The typical structure of a Quantum Mechanical Experiment Preparation : e+ beam Ps beam Target Laser (excitation) First grating Detection : Recording interference pattern Projection on measurement eigenstates Preparation Detection Interaction Propagation Interference Non – ideality : Incoherence Non – ideality : Decoherence 10/10/2017 Quplas CSN2 - July 2015

New Fundamental Physics QUPLAS concept Synergy of technologies developed in different areas as well as new technologies: Positrons and positronium techniques (Como) Positron beams, moderation and plasmas (Como, Milano) Special converters for Ps production in transmission mode (Bath, Milano) Laser excitation for positronium (Milano) Emulsion techniques for precise measurements (Bern) New Fundamental Physics 10/10/2017 Quplas CSN2 - July 2015

Quantum Interferometry (mostly) in the Talbot regime QUPLAS Physics Quantum Interferometry (mostly) in the Talbot regime S. Sala, F. Castelli, M. Giammarchi, S. Siccardi and S. Olivares – Matter-wave interferometry: towards antimatter interferometers. Submitted to J. of Phys. B, Atomic, Molecular and Optical Physics, arxiv:1505.01639 [quant-ph]. Positrons and electrons quantum waves interference (QUPLAS-0) Positronium quantum interference (QUPLAS-I) Positronium quantum dynamics and decoherence studies Positronium gravitational studies : free fall ! (QUPLAS-II) 10/10/2017 Quplas CSN2 - July 2015

The facility: the Como continuous positron beam The VEPAS Laboratory at the L-Ness Politecnico di Milano at Como Center. (R. Ferragut) Slow positron beam. 1. Radioactive source; 2. Electrostatic optics; 3. Sample chamber; 4. HpGe detectors; 5. Cryostat; 6. High voltage protection cage; 7. Power suppliers; 8. Detector electronics. http://www.como.polimi.it/positron Original intensity of the source: 50 mCi Current intensity: ~ 13 mCi Tungsten moderator  reduces the energy from the beta spectrum down to a few eV Electrostatic transport  positron beam 10/10/2017 Quplas CSN2 - July 2015

The general structure A continuous positron beam (better than a bunched beam for interferometry!) Transmission targets (technical focus of development, Bath and Milano) Possible electrostatic system to focus the Ps in the forward direction Laser system to excite Ps in a velocity selective way ! Micrometrix SiNx gratings (made at LNESS) Nuclear emulsions provided by the Bern group. 10/10/2017 Quplas CSN2 - July 2015

Talbot carpets 2 1 Fraunhofer regime setting in when L>>LT The characteristic pattern of the Talbot effect can be used to make sure the observed effect is the Talbot effect for the specified wavelength Units Talbot length Fringes visibility for the given wavelength 2 1 Fraunhofer regime setting in when L>>LT «Ballistic» moiré regime 10/10/2017 Quplas CSN2 - July 2015

The QUPLAS Laser system for velocity-selective excitation of a continuous Ps beam Excitation of Rydberg states : 12 243 nm 2n ~ 732 nm 10/10/2017 Quplas CSN2 - July 2015

The QUPLAS Laser system for velocity-selective excitation of a continuous Ps beam 10/10/2017 Quplas CSN2 - July 2015

Talbot Optics in the Laboratory Classical Optics experiments to guideline the particle experiments µm 10/10/2017 Quplas CSN2 - July 2015

The de Broglie wavelength QUPLAS - 0 Positron beam energy: from a few keV up to 20 keV Reference value: 10 keV Intensity: ~ 4 x 104 e+/s The de Broglie wavelength Given a grating with One can choose b = c = 33 cm To have a 2 µm periodicity pattern on C Setup preparation Exposure to the e+ beam Integration on the emulsion detector C The Talbot length 10/10/2017 Quplas CSN2 - July 2015

An experimental activity that has already started with low-cost tests: QUPLAS - 0 An experimental activity that has already started with low-cost tests: Emulsion exposures to the VEPAS e+ beam 3 exposures made at energies ranging from 6 keV to 20 keV Positron source  Electron source in preparation in the same apparatus (electron emitting tips) : Preliminary result: e+ visible down to 10 keV in emulsions! Quantum Interferometry with 10 keV positrons Quantum Interferometry with 10 keV electrons (in the very same apparatus) a teeny-tiny CPT test (fermion/antifermion comparison never done before) to start with 10/10/2017 Quplas CSN2 - July 2015

Stripes prototype made by Electron Beam Lithography QUPLAS - 0 SiN thickness 200/500 nm 5 mm x 5 mm Micrometric (and nanometric) gratings being developed on SiN substrates Stripes prototype made by Electron Beam Lithography  10/10/2017 Quplas CSN2 - July 2015

Excitation on Rydberg state is necessary. Laser excitation required. QUPLAS - I Positronium Quantum Interferometry concept Positron Interferometry Electron Interferometry Positronium Interferometry An elementary fermion The relevant antifermion The bound fermion-antifermion system (also, the simplest atom) Problems to face : Positronium is a neutral atom Positronium has a very short lifetime Detection of the interference pattern is not going to be easy. Ionization required. Excitation on Rydberg state is necessary. Laser excitation required. QUPLAS – I physics program: Quantum Decoherence with an unusual system Wave function interpretation Optical gratings and laser interaction and cooling 10/10/2017 Quplas CSN2 - July 2015

Samples. Micrometre membranes Synthesis route to the growth of free-standing surfactant-template films of silica (Chemistry Department, University of Bath, Claverton Down, Bath) [1] Calcination (400oC) [1] K.J. Edler* and B. Yang, Chem. Soc. Rev., 2013 42, 3765 10/10/2017 Quplas CSN2 - July 2015

QUPLAS - II Positronium Gravity : why? Answer : to test the Weak Equivalence Principle (test of General Relativity) Universality of Free Fall Matter Weak Equivalence Principle tested on many different systems Torsion Balance Measurement 10-13 level reached Antimatter g not measured Antihydrogen program at CERN (e. g. The AEgIS experiment) Aiming at ~ % accuracy Positronium Matter/Antimatter system ? 10/10/2017 Quplas CSN2 - July 2015

Measuring gravity Methods to measure the Interference Pattern Shift Quantum Talbot Interferometry (pitch of ~ 100 microns) S. Sala et al., submitted to J. of Phys. B, Atomic, Molecular and Optical Physics, arxiv:1505.01639 [quant-ph]. Moiré classical deflectometry (pitch of ~ mm) S. Aghion et al., Nature Comm doi:10.1038/ncomms5538. 10/10/2017 Quplas CSN2 - July 2015

The third method to measure gravity («space – gamma») 3. Simple method of tracing a given velocity selected by the laser (highly efficient on NaI) Three different methods to measure g Talbot interferometry Moiré deflectometry Space-gamma Different picthes for the gratings but similar systematics and blank measurements Entirely different systematics 10/10/2017 Quplas CSN2 - July 2015

Gravity measurement count rate Count rate for a typical gravity experiment 50 mCi source with a RGM moderator (0.4% efficiency)  7 x 106 e+/s e+  Ps conversion (10%) and reemission (30%) by converters  2 x 105 /s Ps solid angle of emission and interferometer geometry (0.1%)  200/s Ps excitation efficiency is high but the spectral selection will introduce 10%  20/s Transparency of the gratings 25%  5/s Sensitivity to g for Ps (only Talbot, interferometric methods) Given 0.5 dots/s on the emulsion, one has, for a very realistic 50% contrast, d3 = 476 μm, Δx = 4 μm : 2% in a WEEK 1% in a MONTH <0.1% in a YEAR 10/10/2017 Quplas CSN2 - July 2015

QUPLAS – 0 activity already taking place QUPLAS Proposal and Financial issues QUPLAS – 0 activity already taking place QUPLAS-0 activity is already supported by : Politecnico di Milano (use of the VEPAS Laboratory) University of Bern (operation, development, use of the emulsion detectors) University of Bath (transmission targets development) The full capital cost (all QUPLAS phases) of the experiment is of about : 150 kEur (moderator) 250 kEur (laser system) < 200 kEur (gratings,beamline,detectors) Request for an ERC Advanced Grant presented (PI: M. Giammarchi) The expense profile in Infn forms is intended to be a worst case scenario Possible FET for the laser part (S. Cialdi) 10/10/2017 Quplas CSN2 - July 2015

The Infn proposal (in preparation, preliminary) Infn Milano : Stefano Aghion (AsRic Politecnico) 50% Monica Bollani (IFN Cnr Politecnico) 20% Fabrizio Castelli (RU Dipartimento) 50% Simone Cialdi (RU Dipartimento) 50% Giovanni Consolati (PA Politecnico) 50% Rafael Ferragut (PA Politecnico) 50% Marco Giammarchi (PR Infn) 50% Mariangela Longhi (RU Dip. Chimica) 20% Giancarlo Maero (RUTD Dipartimento) 15% Stefano Olivares (RU Dipartimento) 50% Matteo Paris (PA Dipartimento) 50% Marco Potenza (RU Dipartimento) 40% Massimiliano Romè (RU Diparitmento) 15% Davide Trezzi (AsRic UNIMI) 20% TOTAL 530% We require Infn approval and will discuss a flexible financial profile 2016 request will focus on the support of QUPLAS-0 (and some laser development) (Major investments will be proposed after QUPLAS-0 will demonstrate the technology) 2016 Costruzione Apparati 18 k Eur (interferometers, laser optics) Consumi 10 k Eur (gratings, targets) Trasferte 10 k Eur 10/10/2017 Quplas CSN2 - July 2015

Backup slides 10/10/2017 Quplas CSN2 - July 2015

The QUPLAS Test of the WEP WEP (Weak Equivalence Principle) : the gravitational acceleration of any object is independent from the object composition. Tested with Matter with a precision of ~10-13 Antimatter has a profound theoretical meaning (Special Relativity and Quantum Mechanics) WEP has never been tested with precision with Antimatter WEP is a Classical Symmetry Theories of Quantum Gravity include non-tensor terms. These gravi-vector and gravi-scalar components can have different signs for matter and antimatter. 10/10/2017 Quplas CSN2 - July 2015

The QUPLAS Lser System 10/10/2017 Quplas CSN2 - July 2015